checking communication error between esp and STM

[DRSpeedster]

Hello everyone,

I'm a student from UHasselt in Belgium and for my master thesis I'm converting an Opel Speedster With an internal combustion engine to an EV. I'm using an Tesla LDU and the logic board swap for this motor from the Openinverter store. After connecting the logic board and the esp I am unable to see the LDU data on my laptop. I keep getting the "Communication problem between ESP and STM" error and don't know what the problem is. The esp is updated and the wiring is tripple checked, the logic board ligthes up in the motor so it is getting power but wil not communicate with the esp.

Can there be a problem with the connector between the inverter and the 23 pin socket?

[uhi22]

Is the ESP connected via CAN or is it directly on the inverters logic board?

[DRSpeedster]

It is connected via CAN.

[uhi22]

In this case the first check is the physical connection:
Resistance between CANH and CANL between 60 and 120ohms? Grounds connected? Do you have an oscilloscope to check the CAN lines? Baud rate correctly configured?

[DRSpeedster]

The resistance between CANL and CANH is 60 ohms, the grounds of the esp and the ground of the motor are connected. If I measure the voltage from the ground of the esp module and the CANL or CANH I get 2,3Vfor both. If I check the CAN lines with the oscilloscope I also get the same value of on bothe CANH and CANL (the value differs a smal amount of 0,1V max). For the baud rate I tried changing the Speed setting on the dash board from 125k to 250k and 500k with no results.

[DRSpeedster]

Small update: When changing the speed from 250k to 500k, the error disappears and the interface works. However, when I start the interface at 500k, it does not work and the error remains. Is there a specific reason for this?

[Jacobsmess]

What is the resistance between CAN H and CAN L? Is there anything else on the CAN circuit?

[DRSpeedster]

The resistance between CANH and CANL is 60 ohms and at the moment it is only the logic board and the esp module on the CAN circuit

[johu]

Small update: When changing the speed from 250k to 500k, the error disappears and the interface works. However, when I start the interface at 500k, it does not work and the error remains. Is there a specific reason for this?

So it probably also works when changing Node Id to something else and back?